1. Field of the Invention
The present invention relates to a plastic hose for transporting fluids and more particularly to a heatable plastic hose for transporting liquids in which a plastic hose is connected over its length with a heating conductor wire useful, for example, for preventing freezing of liquids contained in windshield washer systems of motor vehicles.
2. Background of the Art
Federal Republic of Germany Utility Model Patent No. 85/20,557.5 discloses a hose for transporting liquids. A heating cable is positioned next to a flexible plastic hose and the positioning is maintained by means of a plaited structure, which surrounds the cable and hose and combines both parts into one connected unit. At the respective ends of this unit, a special termination of the plaited structure is provided which prevents unraveling of the plaited structure.
This prior art hose is complicated to manufacture, however, because two individual elements must be combined into a unit by forming the plaited structure around them. Another drawback of the hose is that the plaited structure is pliable and the heating conductor cable fixed to the plastic hose by way of the plaited structure may be displaced by the application of pressure resulting in possible mechanical damage to the cable which could render the unit unheatable. Moreover, the plaited structure is permeable to moisture and dirt so that soiling and corrosive damage of the heating conductor cable may negatively influence the performance and service life of the heatable hose unit.